How To Sanitize A Water System



*To produce a 500 PPM chlorine dosage.


Pellet Weight = 1 gram each, 28 pellets/oz., 454 pellets/lb.

Every new well, or existing water supply system that has been disrupted for service or repair, should be disinfected before it is returned to use.

Water in the well and storage tank should be treated with a strong chlorine solution to destroy disease organisms.

With H2O Chlorination
Water Well Sanitizer Pellets


  • Chlorine is a strong oxidant.
  • Keep pellet containers tightly closed and child resistant locking devices in place.
  • May cause eye damage. Do not get in eyes.
  • May produce chemical burns. Avoid contact with skin and clothing.
  • May be harmful or fatal if swallowed. Keep pellets out of reach of children.
  • Always rinse empty container with water, then destroy.
  • Store pellets in a cool, dry place, away from heat, sparks and flame.
  • Always keep pellets clean and free from any dirt, grease, or other foreign materials.
  • Always use a clean plastic container or scoop to handle pellets, NEVER BARE HANDS OR CLOTH GLOVES. Clean rubber gloves can be used. NEVER INHALE DUST OR FUMES when handling chlorine pellets.

To Add Pellets: Drilled Wells

1. Remove the cap or seal from the casing and measure the depth of the water in the well. Refer to the table to determine how many chlorine pellets should be used. In some instances, removing the seal to measure the water can be a difficult task. It may be easier to estimate well and water depth from the well log or other records.

All pipe lines and fixtures in the distribution system should be rinsed and flushed with chlorinated water.

H2O Chlorination Water Well Sanitizer chlorinating pellets can be used for well, storage tank or cistern sanitization.

The amount of pellets used will depend on the amount of water in the system to be sanitized.

To sanitize a water system with a 500 PPM chlorine concentration, use 12 oz. of chlorination pellets for each 100 gallons of water in the system.

3/4 lb.12 oz.340 pellets
100 gal.100 gal.100 gal.

The table above shows how many pellets by weight to use per 100 feet of water in various diameter wells.

Large Diameter Bored Wells

Calculate the volume of water in the well by determining the total cubic inches or cubic feet of water in the well. Each 231 cubic inches of water is equal to one gallon. Each cubic foot of water is 7.5 gallons of water. Use 3/4 pound of chlorine pellets for each 100 gallons of water in well.

Dissolve pellets in clean, plastic container and add to well. Pour two cups of pellets directly into well. Connect a garden hose to a faucet in water system and run water from hose back down well. When strong chlorine odor is evident in hose water, wash down sides of well with chlorinated water. Proceed with steps 6, 7, and 8 of instructions for drilled wells.

Springs and Cisterns

Mix approximately 1/2 cup of pellets in 5 gallons of water. Use this to scrub the walls of the spring box or holding tank. With a constant flow of fresh water from the spring there is probably no way of retaining the chlorine solution in a reservoir for more than a few minutes. However, the chlorinated water should flow through the pipeline to disinfect the distribution system.

Cisterns can be disinfected in the same way but a source of clean water will be needed to flush the dirty waste out of the system.

Note: H2O Chlorination Water Well Sanitizer pellets are intended to sanitize a water supply system that has been temporarily contaminated, and is not intended to solve a recurring contamination problem.

2. Remove well cap and determine if there is an unobstructed path from the top of the well to the water level. If it is not possible to remove the well cap, remove vent or sanitation access plug.

3. Drop one pellet into the well and listen to hear if it hits the water. If the pellet hits the water, drop one-half (1/2) the number of pellets determined to be needed into the well. These will sink to the bottom and sanitize the lower part of the well.

4. Mix the remaining pellets with a few gallons of water in a CLEAN plastic container and pour solution into the well.

5. In order to mix the chlorine thoroughly throughout the entire water system, it is necessary to recirculate the water in the well. This can be accomplished by connecting a hose to run water back down the well (This also rinses upper portion of well). After approximately 30 minutes of recirculating the water, a strong chlorine odor should be evident. Turn off hose.

6. Bypass water softener and filters and open each water outlet in the water system until chlorine odor is evident at each. This procedure assures that all water in the system is chlorinated.

7. Allow the chlorinated water to stand in the system for at least six (6) hours, and preferably overnight. After this, open an outside faucet and flush system until water runs chlorine-free. Repeat flush operation on each faucet in system.

Caution: Chlorine may break iron deposits, slime and organic material loose. This material will make the water run colored. The material broken loose may plug pump screens. DO NOT CONTINUE TO RUN PUMP IF WATER DOESN’T FLOW.

The high level of chlorine required to sanitize a water system is corrosive to most metals. Chlorine solution must not be allowed to remain in water system more than 36 hours before being com- pletely flushed from system.

8. After the system has been completely flushed, perform a bacterial analysis on the water following all applicable procedures.

Note: Always follow the sanitizing procedure required by applicable state or local laws.

EPA Registered -- Well Sanitizer Pellets are Certified by NSF to NSF/ANSI Standard 60.

© 2012 H2O Chlorination, Inc.
P/N 1017782 Rev. F

Home ~ About H2O Chlorination, Inc. ~ The Well PRO System ~ The LP-3000 System

Links to the .pdf files below will open in a new browser window/tab so you don't lose your place here.
Farm Facts ~ Additional Info About H2O Chlorination, Inc. and Chlorinating
Well Pro Maintenance Manual ~ Limited Warranty ~ LP-3000 Maintenance Manual